1. Field of Invention
This invention relates to extrusion-type, square balers wherein a reciprocating plunger compacts and incrementally moves successive charges of crop material rearwardly in the bale chamber toward and through a constricted outlet, and in particular, to a selective bale ejector for the baler.
2. Description of Related Art
Extrusion-type, square balers have a reciprocating plunger that compacts and incrementally moves successive charges of crop material rearwardly in the bale chamber toward and through a constricted outlet. Because the outlet is constricted relative to the larger main portion of the bale chamber, the previously formed rearmost bale, which is still in the chamber, resists being moved rearwardly by the plunger, creating a back pressure that causes new charges of crop material to be compacted against the previous bale by the plunger as it pushes both the new material and the previous bale toward and through the outlet.
U.S. Pat. No. 5,540,144, which is assigned to the assignee of the present invention and hereby incorporated by reference into the present specification, discloses a selective bale ejector. As explained in the '144 patent, extrusion-type square balers typically have at least two, and sometimes more, bales in the bale chamber at the same time during baling operations. The rearmost bale in the chamber is a finished bale that serves as a moving backstop against which new charges of material are compacted and incrementally moved rearwardly by a reciprocating plunger to create the next bale. While rearmost bales are from time-to-time automatically pushed out of the bale chamber and onto the ground or an accumulating trailer throughout a day's baling operations, there are times when the operator may wish to “prematurely” unload the rearmost bale, but not the second bale, from the chamber, such as when the operator leaves the field after the day's operations or when he moves from one field to another. By leaving the second bale in the chamber, which may only be partially formed at the time of ejecting the rearmost bale, the chamber has a pre-existing backstop for the plunger to work against when operations are resumed. This saves valuable time and money for the operator because starting new baling operations with a totally empty chamber is tedious and time-consuming.
One problem in ejecting only the rearmost bale is that the interface between the rearmost bale and the second bale may be at any one of a number of different locations along the bale chamber when the operator chooses to unload the rearmost bale. In other words, the second bale may be in various stages of completion at the time of ejecting the rearmost bale, such that the space occupied by the second bale in the chamber could range from only a small portion to a large amount, placing the interface anywhere along the bale chamber. Thus, the ejecting mechanism must be able to adapt to a number of different bale positions so as to not also engage and offload the second bale along with the rearmost bale.
However, there may also be some situations wherein the operator does wish to unload both the rearmost bale and the second bale prematurely from the chamber, either simultaneously or one-at-a-time, so as to completely empty the chamber of all crop materials. The ejecting mechanism must be flexible enough to accommodate that instance as well.
While the ejecting mechanism of the '144 patent has performed well, certain shortcomings have come to light over the years. For example, the patented ejecting mechanism requires considerable manual force to set up the selected number of bale ejecting projections or teeth of the mechanism for proper ejection by a hydraulically operated shuttle. Even greater manual force is required if crop residue, dirt or debris accumulates on the working components of the mechanism, causing them to bind up or jam. In addition, the prior ejecting mechanism requires the operator to perform the set up operations on both sides of the baler through two separate but duplicate series of steps, making the set up process both arduous and time-consuming.